Chronic fungal sinusitis in apparently normal hosts.

Several fungal species are capable of causing either noninvasive fungal sinusitis or invasive disease characterized by erosion into mucosa, submucosa, bone, and deeper contiguous structures. The diagnosis of invasive infection becomes firmly established only after histologic demonstration of hyphae within these areas. Computerized tomography and magnetic resonance imaging can assist in distinguishing between invasive and noninvasive disease by outlining bone and adjacent structures. The 2 forms of chronic fungal sinusitis mandate different therapeutic approaches. While patients with noninvasive infection require only surgical removal of hyphal masses and the reestablishment of sinus drainage for a successful outcome, invasive infection necessitates not only thorough surgical debridement of abnormal tissues but may also require prolonged antifungal chemotherapy. All patients require long-term follow-up. Even the combined approach has sometimes proven disappointing during long-term follow-up of disease, rendering investigational therapy appropriate in some patients.